Revert "gpu: nvgpu: cache gpu clk rate"

This reverts commit e9a6d179a42e ("gpu: nvgpu: cache gpu clk rate")

 - Real clock rate doesn't always equal clock rate requested by caller
 - call of clk_set_rate() and update of cached_rate are not atomic
 - Real root cause for Bug 2051688 is in bpmp and gboost design

Bug 2538692

Change-Id: I9248e0c69e2271ed2d0070587db59afa6f8160f2
Signed-off-by: Peng Liu <pengliu@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2109708
(cherry picked from commit cc70f89bb4efd106b81c2da5ecd6cbeb69c990d8)
Reviewed-on: https://git-master.nvidia.com/r/2113647
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Aaron Tian <atian@nvidia.com>
Tested-by: Aaron Tian <atian@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 5 insertions, 14 deletions

diff --git a/drivers/gpu/nvgpu/os/linux/clk.c b/drivers/gpu/nvgpu/os/linux/clk.c
index 36c13577..6575a037 100644
--- a/drivers/gpu/nvgpu/os/linux/clk.c
+++ b/drivers/gpu/nvgpu/os/linux/clk.c
@@ -1,7 +1,7 @@
 /*
  * Linux clock support
  *
- * Copyright (c) 2017-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2017-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -38,13 +38,9 @@ static unsigned long nvgpu_linux_clk_get_rate(struct gk20a *g, u32 api_domain)
         switch (api_domain) {
         case CTRL_CLK_DOMAIN_GPCCLK:
                 if (g->clk.tegra_clk)
-                        ret = g->clk.cached_rate ?
-                                g->clk.cached_rate :
-                                clk_get_rate(g->clk.tegra_clk);
+                        ret = clk_get_rate(g->clk.tegra_clk);
                 else
-                        ret = platform->cached_rate ?
-                                platform->cached_rate :
-                                clk_get_rate(platform->clk[0]);
+                        ret = clk_get_rate(platform->clk[0]);
                 break;
         case CTRL_CLK_DOMAIN_PWRCLK:
                 ret = clk_get_rate(platform->clk[1]);
@@ -66,15 +62,10 @@ static int nvgpu_linux_clk_set_rate(struct gk20a *g,
 
         switch (api_domain) {
         case CTRL_CLK_DOMAIN_GPCCLK:
-                if (g->clk.tegra_clk) {
+                if (g->clk.tegra_clk)
                         ret = clk_set_rate(g->clk.tegra_clk, rate);
-                        if (!ret)
-                                g->clk.cached_rate = rate;
-                } else {
+                else
                         ret = clk_set_rate(platform->clk[0], rate);
-                        if (!ret)
-                                platform->cached_rate = rate;
-                }
                 break;
         case CTRL_CLK_DOMAIN_PWRCLK:
                 ret = clk_set_rate(platform->clk[1], rate);